Old English stingan "to prick with a small point" (of weapons, insects, plants, etc.), from Proto-Germanic *stenganan (cf. Old Norse stinga, Old High German stungen "to prick," Gothic us-stagg "to prick out," Old High German stanga, German stange "pole, perch," German stengel "stalk, stem"), from PIE *stengh-, nasalized form of root *stegh- "to prick, sting" (cf. Old English stagga "stag," Greek stokhos "pointed stake"). Specialized to insects late 15c. Slang meaning "to cheat, swindle" is from 1812.

n.

Old English stincg, steng "act of stinging, stinging pain," from the root of sting (v.). Meaning "carefully planned theft or robbery" is attested from 1930; sense of "police undercover entrapment" first attested 1975.